A major bottleneck in the production of flexible polyurethane foam slabstock is the amount of time and space required to store the foamed slabstock prior to fabrication or shipping. Requisite conditioning for a certain period of time dependent upon the storage temperature and type of foam formulation is needed to permit the foamed product to become fully cured, i.e. develop the inherent property of restitution so that the product when compressed to a lesser size to facilitate shipping can return to its original dimensions once it arrives at the destination and the compressing force has been removed.
In addition, yields of foam are reduced due to the need for oversize cutting to meet end use specifications when the foam product is shipped in compression trailers.
Foam producers have attempted to improve the overall process for making and storing flexible polyurethane foam products by the use of infrared heat lamps on the production line, heating the storage buildings where the foam is allowed to cure, storing the foams for an extended period of time before fabricating or shipping and oversize cutting to compensate for lack of recovery. These solutions to the problem add to the costs and inefficiencies in the overall process from making the foamed product to its arrival at its ultimate destination.
The prior art is replete with examples of tertiary amines that can be used as catalysts alone and in combination for the reaction of polyols with polyisocyanates in the production of polyurethane foams. Catalysts which are generally used in the flexible foam art include, for example, triethylenediamine, bis(dimethylaminoethyl)ether and diemthylethanolamine, optionally in combination with a tin compound.
U.S. Pat. No. 3,786,005 discloses the use of 4-(2-dimethylaminoethyl)morpholine as the principal amine catalyst for the reaction of polyols and polyisocyanates to make polyurethane foams. Example 2 shows its use in a flexible polyurethane foam composition containing a polyether polyol.